


Guard Duty

by LA_Peach



Category: Undertale (Video Game)
Genre: Anal Sex, Fontcest, Love/Hate, M/M, classic fontcest
Language: English
Status: Completed
Published: 2019-01-18
Updated: 2019-01-18
Packaged: 2019-10-12 10:35:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,749
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17465921
Author URL: https://archiveofourown.org/users/LA_Peach/pseuds/LA_Peach
Summary: Sans and Papyrus works as security guards for Determination Inc. One night the monitors start going wonky and in trying to fix it, Sans discovers he is unerringly attracted to his co-worker... even though Sans hates him so darned much.





	Guard Duty

**Author's Note:**

> This was written as a gift for twitter for reaching 100 followers and was featured first on my Patreon before being shown here.
> 
> I'm not great with tags. Please let me know if you'd like something added.

               

                Sans swiped his ID badge to enter Determination Inc., the building where he worked. From the outside it was pretty non-descript, looking like a regular boring office building. But security was tight and very few actually moved in and out of it. Unlike most buildings however, their security division was rather large.

                With two skeletons manning the front desk and two manning the monitor room at all times, Determination Inc. had already far outdistanced any other building in the city. Several guards walked the corridors; one was stationed at the buildings only elevator and still one more was stationed at the buildings back fire exit. This was only the night shift; day shift had even more on duty. They all wore matching guard uniforms with hats and badges and walkie-talkies; they all had nightsticks and they all carried guns.

                None of them were allowed in the lower levels. None of them knew what Determination Inc. did. But skeletons were reliable folk and none of them questioned this, nor did they question the lack of other monsters or even humans among their staff.

                Sans manned the camera room with his partner, Papyrus. He had been instructed via contract not to talk about the extra cameras that showed the strange rooms underground. Sans didn’t much care what they did as long as his job didn’t require him to do much more than watch some monitors all day.

                Oh yeah, and he absolutely _despised_ his partner.

                The pay was great, the job was easy, but every day Sans contemplated just up and leaving this damned place. Papyrus drove him absolutely insane. He spent his evenings seething in anger, unable to pinpoint the exact reasons Papyrus made him so livid. But no matter how hard he tried, at the end of the day he just couldn’t bring himself to quit.

                “Good evening, Sans! Ready to watch some screens?” Papyrus was already in the monitor room, early as always. His uniform was clean and crisp, perfectly ironed, everything about him just screamed ‘regulation.’ Sans hated how damn handsome he looked.

                Sans sat in his chair without responding. “There haven’t been any interesting instances on the cameras for six hundred and twenty five days. Wowie, that’s a record. Shall we bet today is going to be the sixth hundredth and twenty sixth?”

                “God damn it, I hate you.”

                “What was that?”

                “Nothing.” Sans blushed furiously, he couldn’t believe he’d actually said that.

                “Hmm. Camera fifteen is acting funny again.” Papyrus reached across the control panel to fiddle with a toggle switch, turning the camera on and off a few times; brushing against Sans’ leg as he did so. He gave Sans a puzzled look as the shorter skeleton pulled away quickly. 

                Papyrus tried to ignore it and turned his attention back to the camera. Sans gave him lots of mixed signals. Whenever he came into the room he seemed to smile brightly when Papyrus welcomed him, but then devolved into a seething mass of bones and grump. Back when they first met, Sans would crack jokes (although Papyrus didn’t like the jokes much) and chat with him, sometimes share his lunch There were even one or two times when Papyrus caught Sans staring at him.

                He had thought that maybe there was something more than just co-workers between them, but he just couldn’t wrap his head around it. Papyrus tapped camera fifteen’s screen, but the static running across it didn’t go away. Sans leaned in a little closer, squinting at it. “Looks like they are running that strange machine again.” His anger was forgotten for a moment and Papyrus rather enjoyed this now focused and interested part of Sans.

                “Every time they turn it on the cameras start going fuzzy. Do you think they are doing something they don’t want us to see?”

                “I dunno,” Sans rubbed his chin. “Maybe something about the machine is just messing with the feed.” Sans slid off of his chair and under the control console. There he pried off the panel to the underside of the unit and started fiddling with the wires inside.

                “Sans!” Papyrus gasped, “What are you doing? We’re supposed to call tech support if we think there is a problem with the equipment.”

                Sans made a rude noise, not surprised that Papyrus wasn’t willing to even take a look. “Just keep an eye on the cameras, okay?”

                Sans didn’t count himself an expert on anything, but to him the inside of the control panel looked a bit strange. It certainly wasn’t _human_ technology, which filled most of the topside buildings these days. It was full of the tubes and skulls indicative of monster tech… something Sans was fairly familiar with.

                “Camera sixteen is going fuzzy now too.”

                Sans grunted. The cameras were defiantly human tech, so were the display screens. Camera fifteen was relatively close to the strange underground experimental area, camera sixteen was a bit further away. That strange machine of theirs must definitely be on and going strong, affecting cameras further and further away from it. It was always pretty dark but Sans had always thought it look vaguely skull like.

                Things were starting to make sense. The human tech was definitely not one hundred percent compatible with the monster tech.

                Sans, on his back with his hands inside the console, glanced past his feet, intending to speak to Papyrus, but got… distracted. Papyrus stood mostly out of sight, standing just to one side with his palms on the top of the console, but Sans got a pretty good view of everything from the waist down. As lewd thoughts filled his head and he blushed furiously, he reminded himself that he hated Papyrus. He hated his perfect looking body and impressive way his pants filled out.

                Besides, Papyrus was a guy. Sans wasn’t… he didn’t…

                He cleared his throat. “P-Papyrus, any change on those cameras?”

                “No, they are pretty much the s-oh. Camera twelve just died.”

                “Died?”

                “Yeah, it’s gone black.” More interested in the situation now than afraid of breaking the rules Papyrus began scanning the other monitors. “Hmm. Cameras ten through thirteen are showing static.” His brow furrowed as he watched camera twelve come back online, then thirteen and eleven went down, only to come back to static moments later. Then the static itself began to clear.

                “It’s like something is moving and it’s disrupting the camera feed.”

                Sans didn’t answer. He was involved in fiddling with the wires underneath.  Camera fifteen suddenly came back crisper and clearer than it had ever been before and Papyrus could see something moving around in the room there. He couldn’t describe it; he couldn’t even make sense of it.

                “Sans, you should see this. Sans?” he wasn’t answering, Papyrus could hear him mumbling to himself. What was he doing down there?

                “This should go here, maybe? Hmm. This skull is attributed to sight and this one to sound? No no, they both carry multiple functions. Damn, I haven’t fiddled with monster tech in a while…” He jumped, whacking his skull against the console when he noticed that Papyrus had crawled under it with him and seemed to be watching him intently.

                He blushed, rubbing his skull. “Fuck. Papyrus, the hell are you doing?” He tried to ignore the fact that Papyrus was so close to him. He couldn’t understand the physical response Papyrus always elicited in him… his heart racing, his breath quickening, his palms sweating. It had to be hate…

                “Oops, sorry. I didn’t mean to startle you. What are you doing?”

                Sans wanted to tell him to back off, but instead he found himself answering. “The skulls aren’t hooked up right. They don’t work too well with human tech.”

                “Why’s that?”

                Sans wiped a bit of sweat from under his eye. “Human tech works with electrical signals. Monster tech works more with instilled emotions and… Papyrus, why are you staring at me?”

                Papyrus swallowed. “You have some grease on your face,” he reach out, cupped Sans’ skull with his palm and used a thumb to wipe at the smear of grease under San’s eye. The movement was involuntary and he shook a little as he realized what he was doing. Such a familiar gesture! What would Sans think of him?

                “God damn it, Papyrus. I hate you.”

                Papyrus felt his heart drop into his stomach, his worst fears were realized. “W-what?” But he didn’t have much time to ponder it. Sans’ teeth clunked against his, a hand wrapped around the back of his neck to hold him close and a tongue; warm and sweet tasting, slipped into his mouth.

                He knew then, without a doubt, why Sans had been acting the way he had for so long with the dismissive attitude and hateful stares. He smiled despite himself and pulled Sans close. All this time the shorter skeleton simply didn’t understand his own emotions, had been interpreting them wrong.  Papyrus’ trembles stopped. When he knew what he wanted, Papyrus was confidence incarnate. And now that he knew what Sans wanted as well…he smirked.

                “I hate you,” whispered Sans between kisses, tears welling in his eyes, confused and happy and unable to understand why he liked all of this… all he could do was try to convince himself that he didn’t like this, he didn’t _want_ this.

                But not for a moment did he ever try to stop it.

                Papyrus slipped a hand under his back, lifting him up just a tiny bit. Sans wrapped his other hand around Papyrus’ shoulders, mewling as the taller skeleton began lifting his tan coloured, button down shirt. He could already feel his body responding, his pelvis was feeling warm and tingly. He was keenly aware Papyrus already grinding against him, could sense an impressive member disguised under his perfectly ironed, regulation coal black pants.

                Above them, cameras were going in and out as something walked around the lower levels of the building. There seemed to be a bit of a problem going on down there, monster scientists were running around, waving their arms. But of course, Sans and Papyrus saw nothing.

                “Ah!” Sans moaned as Papyrus slipped a hand into his pants. He couldn’t hold back anymore, with Papyrus exploring his intimate parts, probing and tickling and stroking so sweetly, his organs formed. Papyrus reveled in the feeling of Sans coming to life under his palm, feeling a complete ecto-body beneath him; cock, sac and anus all warm to the touch.

                The clink of a belt buckle being undone was somehow the most erotic sound Sans had ever heard.

                Papyrus gently took hold of Sans’ hands and guided it purposely downward. Sans’ panting in his ear was delicious, he loved the little noises the skeleton was making. He adored the little tremble as Sans gripped his ecto-penis, maybe he even made little “Nyeh” noises of his own.

                Papyrus tugged at Sans’ pants, pulling them off. Sans gasped, feeling the cooler air smack against his bones. There was a feeling of finality when Papyrus lifted his legs over his shoulders, gaining perfect access to Sans’ entrance. Sans puffed, his hands made fists in Papyrus’ shirt.

                “Damn it,” Sans swore as Papyrus continued to tease him, just slightly pressing against him with his cock and pulling away again, kissing his neck and caressing his spine and hips.

                “What do you want?” Whispered the taller skeleton, wanting to hear it from Sans.

                “I…” Sans stuttered, trying to work through the fog that had seeped into his skull.

                Papyrus pressed just a little harder.

                “I…”

                Papyrus leaned back, rubbing their cocks together slightly, teasingly, smiling at the small drop of pre-cum on the tip of Sans’ member. “Go on, tell me.”

                Sans lost it. There was a small _click_ as he braced both hands on the floor beneath him and shouted “Damn it, I hate you Papyrus! FUCK ME ALREADY!”

                He was loud enough that he didn’t hear Papyrus’ walkie-talkie respond in near-real time. He let out a loud moan as Papyrus finally pressed himself home.

                “Papy, yes!” he panted as Papyrus began to thrust inside of him. Paps filled him, stretched him, pushed him to his limits. Tears filled his eyes, ran down his cheeks. He couldn’t control them, he didn’t want to. Above him, Papyrus’ handsome skull breathed heavily, his tongue lolling out of his mouth, fully in the moment.

                There was a knock at the door, but neither skeleton heard it. Under the console the small space was filled with the sound of their lovemaking.

                “Papy… I’m gonna… please, harder!”

                “M-me too,” Papyrus responded, picking up the pace and plunging deeper and deeper inside of Sans. Their hips clunked together, their ecto-organs squished and made delicious noises together.

                Sans could hold back no longer, hot cum spewed from him and hit his own ribcage, dripping onto the back of his shirt, a powerful orgasm rocking his whole frame. The sight of it drove Papyrus over the edge, he shuddered. “Nyeh!” he panted, emptying himself inside of the smaller skeleton, filling him… expanding him.

                They gasped together, sharing their breath, unwilling to disengage. Sans gripped at Papyrus with hands that would not uncurl, Paps stroked his femurs gently. Eventually, they both became aware of the knocking on the door. As papyrus finally pulled himself loose and Sans shifted, they heard the distinct click of the Sans’ walking-talkie… turning off.

                Both of them froze, realizing that their entire escapade under the console had been broadcast over the walkie-talkies. Papyrus flushed, all the colour draining from his face until he looked utterly blue. They could be fired for this… who knows if something like that would tear the fragile blooming of this new relationship… Papyrus could lose Sans…

                He scooted out from under the desk while Sans frantically tried to pull up his pants and tuck in his shirt over his swollen ecto-belly. Sans flopped on his chair, hiding the wet stain on the back of it and squishing the cold fluid against his spine in a chilly reminder of what they had just done.

                Papyrus straightened his regulation hat and hoped he didn’t sound as out of breath as he felt. He opened the door to a worried looking skeletal guard. Papyrus could see a few others waiting down the end of the hall, obviously wanting to see what was going on.

                The guard peered past him into the camera monitor room. Noting Sans in his chair with his feet propped up on the console. “You guys… okay in here?” asked the guard.

                “NYEH HEH HEH!” Papyrus boomed, using his disarming, innocent voice that he hadn’t needed to use around Sans in some time. “THE GREAT AND POWERFUL DUO OF PAPYRUS AND SANS NEED NO HELP WITH THESE SIMPLE VIEWING APARATUSES!” 

                The guard’s brow knit together, seeming to notice the dangling wires under the console itself. “We heard some… strange things over the walkies.” She coughed into her hand, “You guys having technical difficulties in here?” Her own cheeks were flushed in embarrassment, unwilling to ask directly if they had just been fucking in the monitor room. Papyrus counted on that, neither of them would say anything definitive. 

                “NOTHING THAT I CAN’T HANDLE, FELLOW GUARD!”

                “Well, if you’re sure.”

                “CERTAINLY! TIME TO GO BACK TO YOUR POST, GOOD GUARD MA’AM! YOU ARE NOT RANKED TO VIEW THE MONITORS, WOULDN’T WANT TO UPSET THE HEAD OF SECURITY, WOULD WE?”

                “Erm, um,” she cleared her throat. “No, no of course not. Let us know if you guys need anything, okay?”

                “INDEED, VERY NICE OF YOU, MA’AM! HAVE A GOOD NIGHT, NOW!” With that, Papyrus closed the door and leaned against it, letting out a sigh of relief when he heard the self-locking mechanism click into place.

                He opened his eyes to find Sans tapping at the screens on the console again, viewing the strange thing moving around on the lower levels.  When Papyrus joined him, laying a hand on the small of his back, he largely ignored it. The familiarity however, made Papyrus smile.

                “What do you think it is?” asked Papyrus.

                “Dunno. Can’t tell. Maybe I can get the rest of these cameras working as well as camera fifteen.”

                “Do you… want to get back under the console?”

                Sans blushed, and cleared his throat. “Uh… yeah. S-sure.”

                “Do you really hate me?” the blunt question did not seem to catch Sans by surprise.

                He smiled widely. “So damn much.”

                Papyrus just laughed. “We will be more careful, this time.”


End file.
